The gunman in the mass shootings at the Washington Navy Yard, Aaron Alexis, had a history of violent outbursts, was at least twice accused of firing guns in anger and was in the early stages of treatment for serious mental problems, according to court records and U.S. law enforcement officials.

Maryland lawmakers are calling for strengthened gun laws in wake of the massacre at Sandy Hook Elementary School in Newtown, Conn., where a 20-year-old gunman killed 20 children and six adults last week.